QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Seward, AK

USGS: 17 km SSE of Lowell Point, Alaska

3:35 am AKDT, Mar 20, 2019 · · 8.2 km deep · released about 15 lb of TNT

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Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
3:35 am AKDT on 20 March 2019 ()
Where
21 km (13 mi) SSE of Seward, AK · earthquakes near Seward
Magnitude
M 1.8 (ml)
Depth
8.2 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2727 days ago

A magnitude 1.8 earthquake was recorded 21 km (13 mi) SSE of Seward, AK, at 3:35 am AKDT on 20 March 2019 (11:35 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

Earthquakes near other towns within 30 km: Bear Creek.

How big was it?

This earthquake released about 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 lb of TNT

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 11 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.6 3 km SW of Bear Creek, Alaska · 25 km NNW of this epicentre
  2. 6.3 37 km SSE of Lowell Point, Alaska · 20 km SSE of this epicentre
  3. 6.1 25 km WSW of Chenega, Alaska · 50 km E of this epicentre
  4. 6.0 54 km SE of Lowell Point, Alaska · 38 km SE of this epicentre
  5. 5.9 33 km SSE of Lowell Point, Alaska · 16 km SSE of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 59.9236, -149.3321. Map © OpenStreetMap contributors.

Aftershocks so far

60 earthquakes have been recorded within 50 km since this one.

  1. 1.8 Kenai Peninsula, Alaska
  2. 2.4 15 km ESE of Lowell Point, Alaska
  3. 1.5 13 km E of Lowell Point, Alaska
  4. 2.3 25 km SSE of Lowell Point, Alaska
  5. 1.6 53 km SSW of Lowell Point, Alaska
  6. 1.5 34 km ESE of Lowell Point, Alaska
  7. 2.6 13 km ESE of Lowell Point, Alaska
  8. 1.6 44 km SSW of Lowell Point, Alaska
  9. 2.0 26 km SE of Lowell Point, Alaska
  10. 2.6 31 km ESE of Lowell Point, Alaska
  11. 1.6 12 km ESE of Lowell Point, Alaska
  12. 1.5 19 km SW of Lowell Point, Alaska
  13. 1.7 13 km NW of Bear Creek, Alaska
  14. 1.7 22 km SW of Lowell Point, Alaska
  15. 2.0 18 km SW of Lowell Point, Alaska

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.